1. Field of the Invention
The present invention relates to an information processing device capable of updating a stored program.
2. Description of the Background Art
In recent years, many electric devices operate according to control programs stored in the devices. The control programs are updated for the purposes of overcoming disadvantages in operation of the devices, adding new functions to the devices and others.
In many cases, a new control program (which will be referred to as an “updated program” hereinafter) is provided together with a determination program for determining whether a control program, which is currently stored in the device (and will be referred to as a “current program” hereinafter), is to be updated or not. A program provider provides the determination program on the assumption that a user not having sufficient information about the device may update the control program.
As examples of the device and method for updating the control program, Japanese Patent Laying-Open No. 2000-207180 has disclosed an information processing device and a program rewriting method, in which a determination routine for determining whether a program in the device is to be rewritten or not is stored in a memory card together with a program for rewriting, and the device executes the routine on the memory card to determine whether the update is necessary or not so that the determination of whether the program is to be updated or not is performed individually according to each of various environmental changes after shipment of products.
Japanese Patent Laying-Open No. 2001-256057 has disclosed an update method for a control program of a service device, which is formed of various kinds of hardware, as well as the service device. The service device performs update processing by identifying an update program suitable for the device itself, and thereby can correctly update the program even when such a change is made in structure that cannot be dealt with by the update program incorporated into the device.
For preventing occurrence of a problem that the device becomes inoperable due to rewriting of the control program, many conventional determination programs are configured to determine that the control program cannot be updated when an execution condition set in the updated program does not match with an execution condition set in the current program. The execution condition is information, e.g., related to a structure of a device executing the control program.
However, even when the execution condition of the updated program does not strictly match with that of the updated program, devices having certain structures can execute the updated program in some cases. Even in such cases, when the update processing is attempted according to the determination program, the determination program determines that the control program cannot be updated. Therefore, the control program is not updated.
Specific examples will now be described. For example, it is assumed that there is a disc reproducing device of reproducing video audio information recorded on a disc such as a CD-ROM (Compact Disc Read Only Memory) or a DVD (Digital Versatile Disc), and a control program is stored in a flash memory included in the device. The disc reproducing device can reproduce only the video audio information recorded only in the NTSC (National Television System Committee) system.
When this disc reproducing device reproduces the video audio information recorded in the PAL (Phase Alternation by Line) system, the video audio information is reproduced according to the NTSC system. The vertical frequency in the NTSC system is generally 60 Hz, and the vertical frequency in the PAL system is generally 50 Hz. Therefore, when it is attempted to reproduce the information recorded in the PAL system, disadvantages such as a disturbance in picture occur due to a difference in vertical frequency.
It is assumed that a device manufacturer has prepared ten thousand flash memories, which have stored programs for reproducing video audio information, e.g., in the NTSC system, for manufacturing disc reproducing devices. It is also assumed that five thousand flash memories among the ten thousand memories are mounted on the products without changing the programs. The other five thousand flash memories are mounted on disc reproducing device reproducing the video audio information in the PAL system.
In many cases, a circuit (decoder circuit) reproducing the video audio information recorded on the disc is operable in both the NTSC and PAL systems. Therefore, it is assumed that the device manufacturer has considered that it is not necessary to prepare newly the flash memories storing the program reproducing the video audio information in the PAL system, and it is merely required to rewrite the control program stored in the five thousand flash memories.
However, the execution condition (the record system of the video information to be reproduced) of the updated program is set to the PAL system although the execution condition of the current program is set to the NTSC system. According to the conventional method, therefore, the determination program determines that the program cannot be updated, because there is a difference in execution condition between the programs. The device manufacturer must execute another method for updating the control program. For newly updating the programs in a factory of the device manufacturer, a large number of devices must be processed so that operators must perform time-consuming works.
For reducing the required labor and time, such a method may be envisaged that the current program is forcedly rewritten and replaced with the updated program without executing the determination program. However, when a failure is found in an operation of the devices after the update of the program, or when the devices do not operate after the update of the program, the device manufacturer must identify the cause at much expense in time and effort.